The ability to measure a human's physiological signals is vital in monitoring, evaluating, and diagnosing the physiological status and health of an individual. Parameters such as heart electrical activity, physiological sounds, heart rate, oxygen saturation, respiration rate, blood pressure, and body temperature can all provide critical information about an individual's health. For example, an electrocardiogram, commonly referred to as an EKG or ECG, is a tool that health care providers use to monitor the bioelectrical activity of the heart. As the heart contracts to pump blood throughout the body, it enters various stages of depolarization and repolarization. These stages of depolarization and repolarization correspond to the contraction and relaxation of different areas within the heart. By measuring electrical signals associated with each heartbeat, cardiologists are able to identify abnormalities that exist in a patient's cardiac cycle.
In clinic settings, such as an ambulance, an operating room, and an intensive care unit, physiological parameters relating to a patient's vital signs are displayed for care providers so that the patient can be easily monitored. Physiological parameters such an ECG are conventionally measured using gel-coated electrodes adhered directly to a patient's skin by medical personnel and require medical personnel to actively participate in the measurement. The large number of wires associated with the electrodes and other measurement devices, however, can severely inhibit a medical team's access to the patient and can slow response time. Often, electrode adhesives fail if the skin is burned, bloody, or otherwise traumatized. Medical personnel may need to resort to placing electrodes and other measuring devices on a patient's back, legs, and in other sub-optimal locations due to problems with the standard placement locations.
Previous work in developing alternative bioelectric sensing systems, such as ECG systems, has primarily focused on enabling low cost mobile monitoring solutions or improving the accuracy and reliability of ECG signals through noise reduction or electrode design. Many low cost home monitoring devices, for example, primarily provide heart rate readings without real time ECG signals as would be needed in a clinical setting. Current higher end systems still rely on “sticky pads” connected by a cable to make contact to the patient. The solutions that transmit bioelectric signals wirelessly to display machines also rely on using several sticky pads to make contact to the patient. Additionally, all current approaches require a conscious effort on the part of medical personnel to attach electrodes to a patient and/or to position a sensing device in a specific location next to a patient so that physiological data can be monitored and displayed. There is therefore a need for systems and methods that can provide reliable monitoring of a patient's physiological parameters without requiring electrodes to be adhered to a patient, without the use of wires attached to the patient, or even without medical personnel assistance.